Heat treating furnaces



June 4, 1968 E. MARTIN HEAT TREATING FURNACES 3 Sheets-Sheet 1 Filed Sept. 14, 1965 INVENTOR Joseph &Markin A'ITORNEY BY :a %04 %JM a NCV/x June 4, 1968 E. MARTIN HEAT TREATING FURNACES E Sheets-Sheet 2 Filed Sept. 14, 1965 INVENTOR Joseph E. Mo rti A'I'TORNEY AL z June 4, 1968 J. E. MARTIN 3 3 HEAT TREATING FURNACES Filed Sept. 14, 1965 3 Sheets-Sheet 5 amw INVENIOR ATTORNEY Joseph E.Mortin ew .f a g m u u o mm 4 nz N m: mm 0 i. w L 3. H J m: o u m u wv ku un m mu. \N \k ut. mm m 3,386,719 HEAT TREATING FURNACES Joseph E. Martin, 19256 John R St., Detroit, Mich. 48203 Filed Sept. 14, 1965, Ser. No. 487,229 16 Claims. (Ci. 263-34) ABSTRACT OF THE DISCLOSURE My invention comprises a rotary horizontal retort furnace having a hollow tumbling bar for tumbling the work While controlled atmosphere is introduced under the work through openings in the tumbling bar where it can only pass through the work, the retort capable of being rotated for simultaneously tumbling and progressing the work within the retort.

The present invention relates to improvements in heat treating furnaces, and more particularly to a heat treating furnace in which the workpieces are uniformly subjected to various atmosphere gases which pass upwardly around the workpieces in the retort, and to provide a heat treating furnace in which the feed and discharge of the workpieces can be quickly and easily controlled and regulated.

One object is to provide a heat treating furnace having a retort which is provided with a perforated tumbling bar to permit atmosphere gases to pass therethrough and be directed upwardly around the workpieces so that the same will be uniformly subjected to the various atmosphere gases employed in heat treating processes.

Another object is to provide a heat treating furnace in which a recirculating blower is mounted in one end of the retort to circulate atmosphere gases through the perforated tumbling bar throughout the entire length of the retort.

Another object is to provide a heat treating furnace having a retort discharge control structure which can optionally be used for permitting discharge of the retort contents when the retort is angularly displaced 180 from its normal Operating position and used as a feed chute structure when in a normal Operating position when the retort is at rest.

Another object is to provide a heat treating furnace and an approved retort structure therefor having a longitudinally extending inverted V-shaped tumbling bar to agitate the workpieces during oscillation of the retort, and to provide said tumbling bar with a series of spaced orifices for the passage of atmosphere gas in a direction upwardly around the workpieces passing through the retort' so that the workpieces will be unformly subjected to the atmosphere gas throughout the entire length of the retort.

Another object is to provide a heat treating furnace in which one end of the retort is provided with a cone-shaped member which can optionally be provided with feed and discharge openings for discharging the workpieces to the quench tank, or for feeding the workpieces to the retort when the same is angularly displaced 180".

Another object is to provide a heat treating furnace in which the retort is provided at one end with a bale wall having an angularly inclined portion adapted to cooperate with the cone-shaped member so that rotation of the retort to a selected position will move the angular portion of the end wall into registry with the discharge passage of the cone-shaped member while in another position the angular wall can be moved into registry with a feed chute to permit workpieces to be fed to the retort from a suitable hopper.

Another object is to provide an opening in said bafiie wall in communication with said tumbling bar to permit atmosphere gases to be fed to the retort during the heat treating process.

States Patent O Another object is to provide a heat treating furnace in which both ends of the retort project through the end walls of the furnace structure, and which provides a small clea'ance for heat loss and in which the atmosphere gases are confined within the retort and are prevented from escaping to the area between the retort and furnace housng.

Other objects and advantages of the invention will become apparent during the course of the following description of the accompanying drawings wherein:

FIGURE 1 is a vertical cross-sectional view showing a heat treating furnace having a retort constructed in accordance with the present invention with a baffie Wall at one end provided with an angular portion and a longitudinally extending perforated tumbling bar for admitting atmosphere gas to the workpieces throughout the entire length of the retort.

FIGURE 2 is a vertical cross-sectional view of a modified form of the invention showing a heat treating furnace provided with a longitudinal perforated tumbling bar and a feed and discharge arrangement at one end of the retort.

FIGURE 3 is an enlarged vertical cross-sectional view taken longitudinally through the retort to show the various details of Construction.

FIGURE 4 is an enlarged longitudinal vertical sectional view similar to FIGURE 2 showing the manner in which the retort is positioned for dscharge and in a position displaced 180 angularly from that shown in FIGURE 3 in which the `cone-shaped member is employed for charging the retort from a suitable hopper at the same end of the retort that the workpieces are discharged.

FIGURE 5 is a vertical cross-sectional view taken on line 5-5 of FIGURE 3 looking in the direction of the arrows to llustrate one of the perforated plates in the retort, and

FIGURE 6 is a horizontal cross-sectional view through a fragmentary portion of the retort taken on line 6-6 of FIGURE 3 and looking in the direction of the arrows to illustrate the tumbling bar and the manner in which the same is perforated on opposite sides of the inverted V-shaped portion shown in FIGURE 5.

In the drawings, and more in detail, attention is first directed to FIGURE 1 wherein there is shown a heat treating furnace of the retort type which is similar in construction to the one illustrated in my Patent 3,144,245, in that the retort is oscillated and independent means is provided for reciprocating the retort to control the speed of the workpieces and subject the same to various time periods at a pre-selected temperature.

In FIGURE 1 there is shown a heat treating furnace housing generally designated 5 having an external shell 6 lined with refractory walls 7, 8 and 9. The heat treating housing 5 is provided with a series of transversely extending panel beams 10 to 13 inclusive, and uprights 14 to 17 are connected to the opposite ends of the channel members 10 to 13 inclusive. Thus, the heat treating furnace housing is rigidly supported on a suitable floor surface.

Supported by the uprights 14 to 17 inclusive is a longitudinal channel member 18 arranged one on each side of the longitudinal axis of the furnace 5. The pair of opposed channel members 18 project beyond the ends of the furnace as `at 20 and 21 and are supported by additional vertical supports 22 and 23 suitably connected to the ends of the extensions 20 and 21.

Reciprocably guided by the opposed channel members 18 is a longitudinal carriage 24 having a series of spaced rollers 26 for guiding the carriage 24 to and fro. The carriage is provided with suitable transverse channel members 27 welded in place and connected to one of the channel members is a link arrangement 28 which is pivotally mounted on a support 29 connected to the uprights 14. A reciprocating motor is mounted on a base 31 as at 30, and said motor is connected to the linkage 28 by a lever 32 pvoted on the brackets 29 as at 33. The motor 30 may be operated by pressure fluid including a piston reciprocably mounted in the casing 30 having its connecting rod 34 connected to the link 32. Thus, when the motor is energzed such as by pressure fluid, a suitable control valve in the motor distributes the pressure fluid to opposite ends of the cylinder and reciprocates the carriage formed by the channel members 24 and 27.

Extending npwardly from one end of the carriage 24 is a pair of angle bars 35, while at the opposite end of the carrage sets of angle bars 36 are arranged in pairs to form hearing supports for the furnace retort.

The retort 38 has cone-shaped end portions 39 and 40 provided with tubular extensions 41 and 42 respectively. The tubular extension 41 extends through an opening 43 in one end wall of the casing 6 and in the refractory wall 8, and said tubular extension is supported by a watercooled bearing structure 44 supported by the spaced pair of uprights 35 which are welded or otherwise connected to the carriage 24.

The other conical end 40 of the retort 38 is received within a cone-shaped housing 45 having a tubular extension 46 which is affixed to the frame structure 48 on the upper ends of the uprights 36 by means of a radial plate 49 aixed to the tubular extension 46. Yielding spring members 50 are connected to the plate 49 by plungers 51. Thus, the yielding spring members 50 urge the conical housing 45 into engagement With the cone-shaped end portion 40 of the retort 38, and the cylindrical portion 46 of the housing 45 is reciprocably and rotatably mounted in an opening in another end wall of the casing 6 and refractory end wall 9 as at 53.

The superstructure 48 is connected to the carriage 24 by means of a pair of uprights 60 which are welded to the superstructure and secured to one end of the carriage 24 is a plate 61 having a reduction gearing 62 which is driven by an electric motor 63-. The power takeofl shaft 64 is provided with a sprocket wheel 65 which is drivingly connected to a sprocket wheel 66 by means of a sprocket chain 67. The sprocket wheel 66 is connected to a drive shaft 68 supported on a suitable water-cooled bearing 69, and said drive shaft 68 is tubular providing a conduit 70 for the entrance of carborizing gases and various other atmosphere gases for heat treating metal. The reduction gearing 62 is of the oscillatory type to rotate the drive shaft 68 alternately in opposite directions, and said drive shaft is connected to the reduced cylindrical portion 42 of the retort as at 71. A bearing seal 73 prevents escape of atmosphere gases between the cylindrical portions 42 and 46 and said seal may comprise a pair of pressurized plates forming anti-friction mutually spaced hearing surfaces.

One end of the retort is provided with a bafile wall 74 having an opening 75 in its lower portion and an inclined upperportion 76 extending in a direction toward the end wall 9. The conical housing 45 is provided with an opening 77 and the retort 38 is provided with an opening 78. A downwardly extending tubular extension 79 is formed on the conical housing 45 and extends downwardly through an opening 80 in the refractory wall 7 and passes downwardly to a quench tank 81 which is mounted beneath the furnace structure and is adapted to receive heat treated articles after they pass through the conduit 79 and its extension 7911 which may be submerged in the quenching liquid contained in the tank 81. Thus, the sprocket chain 67 can be released -frorn its drive and the drive shaft 68 rotated 180 from the position shown in FIGURE 1 so that the opening 78 will register with the opening 77 and upon continued reciprocation of the retort the heat treated articles can be discharged to the quench tank without the loss of carborizing or other atmospheres.

Extending longitudinally along the lower pe'iphery of the retort 38 is a tumbling bar generally designated 82,

. 4 i v and said bar comprises a plate having a longitudinally extending V-shaped rib 86 provided with a series of equidistan-tly spaced longitudinally arranged orifices 84. One end of the tumbling bar 83 is in communication with the opening 75, and when various atmosphere gases are fed to the connection 86 they will pass through the tubular drive shaft 68, cylindrical member 42 and opening 75 where they will pass through the entire length of the tumbling bar `83 and will be discharged upwardly through the orifices 84 and through the various workpieces throughout the entire length of the retort.

Vertical uprights 8 8 are connected to the carriage 24 and support a feed hopper 89 having a discharge chute '90' which is connected to the tubular extension 41. A control gate 9-1 is provided for the chute 90 and is actua-ted by a fluid motor 92. The tubular extension 41 is rotatably mounted in a water-cooled thrust bearing 93 which moves to and fro with the carriage 24 and similarly reciprocates the retort 38 while permitting rotation thereof in the bearing 44.

The heat treating furnace 5 is provided with a series of heaters 94 which surround the retort 38 and a suitable thermocouple 96 is mounted in a tube 97 supported in the tubular extension 41 and is adapted to indicate the temperature within the retort 38 on a gauge indicator 98.

:In operation, the w-orkpieces are fed to the retort 38 after the heaters 94 have been ignted and -the motors 30 and 63 are energized to reciprocate and oscillate the Workpieces during their travel from one end of the retort to the other. The atmosphere is supplied to the retort through the connection 86 and passes longitudinally through the tumbling bar 83 and is discharged through the orifices 84 and passes upwardly through the small workpeces. As the retort 38 is oscillated -the tumbling bar 82 agitates the Workpieces while the reciprocation of the retort feeds the Workpieces in a shuffle fashion. The reciprocating motor 30 is of the type which will move the retort 3 8 rapidly in one direction and slowly in the oppbsite direction. After the workpieces have been subjected to the atmosphere gas at a preselected temperature for a predetermined time period the retort 3 8 is ro-tated 1'80 so that the opening 78 in one end thereof registers with the opening 77 in the cone-shaped housing 45 whereby -the Workpeces will slide down the inclined portion 76 and be discharged into the duct 79' leading to the quench tank &1.

In the form of the invention shown in FIG URE 1 the carborizing and nitriding atmospheres are slghtly circulated due to their escape at one end of the retort adjacent the feed h-opper. The opposite end is effectively sealed by the sealing ring structure 73 and the escape of atmosphere gases through the duct 79 is prevented by the extension 'ma being submerged in the quenching liquid in the tank 81.

The nvention shown in FIGURES 2 to 6 inclusive embodies a retort furnace structure generally designated Sa which is similar to that shown in FIGURE 1 and includes a furnace shell a having a refractory furnace wall 7a having end walls 8a and -9a. The furnace structure is supported by uprights 1`4a to 17a inclusive connected to a suitable base member 1841 and the upper ends of -the uprights are connected by transverse channel members 1011 to -13a inclusive and support the furnace structure Sa. Opposed channel members 1961 are supported by the up- -rights and form tracl ways for a carriage 2411 which is provided with rollers %a engagng the lower flanges of the opposed channel members 1'9a. The channel members are provided with extensions 20a and 2*1a which project beyond the furnace wa-lls and the carriage 24 is reciprocated by suitable lnkage 28a connected to one of the cross members 27a of the carriage. Brackets 2911 are connected to the uprights 14a and pvoted between the brackets is a lever 3 2a as at 3311. A motor 3011 of the exp'ansible chamber type has its piston connected to a piston rod 3'4a which is drivingly connected to the carriage 21411 through the connection 34b, pivoted lever 3211 and linkage 2811.

'Mounted within the furnace casing a is a cylindrical retort 3811 which has one end extendng through an opening 4 111 in the end Wall 811 and said end is provided With a plug 100' held in place by aretaining cover 101. The retaining cover is shaped to provide a channelway and a pair of supporting brackets 108 are suitably connected to the carriage 2411 and said bearin g bracket is shaped at its upper end to provide a foot 104 for supporting a roller housing 105. Rotatably mounted in the roller housing 105 is a series of rollers 106 which are received in the channelway .102 and support one end of the retort 3811. An electric motor -7 is supported on the carriage 2'411 by means of a bracket support 1113 and said motor is provided with an armature shaft fitted with a pulley 109. The pulley 109 is provided With a belt 116` which is drivingly connected to a pulley 1:11 on a hollow shaft 112 which is r-otatabiy mounted in the plug 109'. A radial blade impeller 1 13 is mounted on the inner end of the shaft 112 and said shaft rotates independently of the oscillatory movement imparted to the retort 3811.

`A transverse bafile wall 114 is mounted at one end of the retort 3811 and said bathe wall is provided with a series of apertures 115 (FIGURE 5).

The opposite end of the retort 3811 is cone-shaped as at 4011 and terminates in a reduced cylindrical portion 4211. A cone-shaped housing 4511 has a cylindrical portion 45b provided with openings 77a and 7'7b arranged in angularly dsplaced relation of 180.

Mounted on the end of the carriage 2411 is pair of vertical uprights 3611 having a superstructure embodying frame members 3811 and supported at the extreme upper end of the uprights 3611 is a hopper 8911 having a feed chute 90a which terminates in an angular portion 120 adapted to register with the opening 77b. A control gate 9211 is controlled by a suitable motor 9211 to regulate the discharge of workpieces from the hopper to the retort 3811. A baflle wall 7411 is provided at one end of the retort and is provided with an inclined upper Wall portion 7611 which is inclined in the same direction as the angular portion 120 of the feed chute so that the retort can be charged with Workpieces when the retort is in its position shown in FIGURE 2. The retort is adapted to oscillated and angularly dsplaced 360 by means of a gear reduction unit 6 211 mounted on a plate 6111 on the carriage 2411. An electric motor 6311 is connected to the gear unit to oscillate the shaft 6411 alternately in opposite directions and within a range of 360. Mounted on the drive shaft 64a is a sprocket wheel 6511 which is drivingly connected to a similar sprocket wheel 6611 on a drive shaft 6811. The drive shaft is the same as before and is supported on a suitable hearing 6911 connected to one of the superstructure supports 48a. The inner end of the tubular shaft 68a is enlarged and connected to the tubular portion 4211 of the retort as at '7111. The cone-shaped housing 4511 is provided with a tubular extension 4611 having a radial flange 4911 which is connected to yieldng spring members 50a by connecting rods 5111. Thus, the conical housing 4511 is yieldingly urged into engagement with the conical end portion 4011 of the retort. A sealing ring 7311 engages the tubular extension 4211 and a fiange 73b on the tubular extension 4611 to seal the space between said extensions. A pressure ring 73c is provided for urging the scaling ring 73 in position (FIGURE 3). The retort is provided with a combined filling and discharge opening 125 which is adapted to register with the opening 7711 in the chute 9011 during feeding of workpieces to the retort when the same is in the position shown in FIGURE 3 and to permit discharge of the workpieces to the chute 7811 leading to the quenching tank 8111 when dsplaced 180 as shown in FIGURE 4.

By controlling the motor 6311 the retort 3811 may be moved from the position shown in FIGURE 3 to that shown in FIGURE 4 so that the articles after being heat treated will pass through the extension '7911 which is submerged in the quench tank and wiil deposit the artciles therein.

A thermocouple tube 9611 extends through the tubular shaft 6811 and also through the bafe wall 7411. The opposite end may be connected with a temperature gauge as before.

Mounted between the bathe wall 7411 and the end plate 114 is a tumbling bar formed of a plate 82a having a V-shaped central portion 8311 provided with apertures 8411. The plate 8211 is welded in place as at 82b to the inner periphery of the retort 3811, and said plate is further provided with a series of apertures 83b on opposite sides of the inverted V-shaped portion 8311.

It will thus be seen, that the retort shown in FIGURES 2 to 6 inclusive can be loaded and discharged from one end thereof, and this can be accomplished by slightly tilting the furace structure while feeding the workpieces from the hopper 8911.

Atmosphere gas for nitriding and carborizing is supplied through a pipe from a suitable source (not shown) and said pipe 156 is connected to a rotary coupling 151 afiixed to the outermost end of the rotary shaft 112.

In operation, the burners 9411 which are mounted in the casing 511 as before, 'are ignited and permitted to burn until the temperature within the furnace housing 511 reaches a predetermined degree. The motors 3011 and 6311 are then energzed selectively to impart either reciprocating or oscillating motion to the retort 3311. Similarly, the motor 107 is energized to start the radial blade impeller 115. With the retort 38a in the position shown in FIGURE 2 workpieces are fed from the hopper 8911 to the inclined portion 120, where they fall upon the inclined wall '7611 of the bafiie wall 7411 and are then deposited upon the tumble bar 8211. Proper atmosphere gas for carborizing, nitriding or the like is admitted through the hoilow shat 112 where it enters the chamber in which the impeller 113 is rotated. The atmosphere gas is then passed along the channelway 151 (FIGURE 6) and is discharged upwardly through the openings 8411 and 831) where it passes through the workpieces and is returned from the retort 3811 to the impeiler 113 through the orifices 115.

After the Workpieces have been heat treated the shaft 6311 is rotated to turn the retort 3311 from the position shown in FIGURE 3 to the position shown in FIGURE 4, whereupon the heat treated articles will pass through the opening 125 which is uncovered by the inclined wall portion 7611 and said workpieces passed through the duct 78a to the quenching tank. The retort 3811 is then returned as before to the position shown in FIGURE 3 for a new cycle of Operations.

The oscillating gearing 6211 is similar to that described in FIGURE 1 and is provided with a suitable control mechanism for permitting the motor 3611 to rotate the retort in both forms of the invention an anngular distance of approximately from that shown in FIG- URE 3 to the position shown in FIGURE 4 and then returned to the Operating position.

It is to be understood that the forms of the invention herewith shown and described are to be taken as preferred embodiments thereof, and that various changes in the shape, size and arrangement of parts may be re sorted to without departing from the spirit of the invention or the scope of the subjoined clairns.

What I claim is:

1. In a heat treating furnace, comprising a horizontal refractory lined casing dening a heating chamber, inside walls defining a generally elongated tubularly outlined rotatable retort; tumbling and atmosphere conducting means including inwardly turned tumbler walis forming an elongated closed duct arranged adjacent and lengthwise said retort inside walls, a series of spaced orifices in said tumbler walls interconnecting with said duct on the inward side only, said duet having an inlet opening at one end thereof for conducting controlled atmosphere through said inlet opening inwardly through said tumbler wall orifices substantially the full length and extent of said tumbler walls, and means for rotating said retort within said casing simultaneously with the introduction of said controlled atmosphere.

2. A heat treating furnace as set forth in claim 1 in which said means for agitating said retort within said heating chamber comprises means for imparting oscillatory motion thereto and independent means for imparting reciprocating motion thereto.

3. A heat treating furnace as set forth in claim 1 in which said longitudinally extending wall means is provided with an inverted U-shaped rib.

4. A heat treating furnace as set forth in claim 1 in which said longitudinally extending wall means is provided with a longitudinally extending inverted V-shaped rib.

5. A heat treating furnace as set forth in claim 1 in which said longitudinally extending wall means is provided with a longitudinally extending rib and the orifices in said wall means are disposed on opposite sides of said rib and along the upper portion thereof, said orifices providing a fricton surface for engaging the workpieces and feeding the same when longitudinal reciprocating motion is imparted to said retort.

6. In a heat treating furnace, comprising a horizontal refractory lined casing defining a heating chamber, a retort including inside walls defining a generally elongated tubularly outlined member mounted to eXtend horizontally in said chamber and extending longitudinally thereof, longitudinally extending Wall means in said retort including inwardly turned tumbler walls having its edges secured to the inner peripheral wall of said retort to form a duct for supplying controlled atmospheres of different compositions to said retort, said wall means being provided with a series of longitudinally spaced apertures on the inward side only to permit said atmosphere to be distributed throughout the length of said retort and uniformly pass around workpieces fed therethrough, said duct having an inlet opening at one end thereof only for conducting controlled atmosphere through said tumbler wall orifices and means for feedng atmosphere gases to said duct.

'7. In a heat treating furnace, comprising a horizontal refractory lined casing defining a heating chamber, a retort extending longitudinally in said heating chamber, means for feeding workpieces to one end of said retort, means for discharging workpieces from said retort, transverse wall means in said retort, a longitudinally extending tumble bar in said retort including inwardly turned tumbler walls forming a closed chamber With the inner periphery thereof for conducting atmosphere compositions to said retort, said tumble bar being provided With a series of spaced openings to permit the uniform distribution of said atmosphere compositions, and said wall means being provided with an inlet opening for conducting atmosphere compositions from one side of said wall means to said tumble bar chamber.

8. In a heat treating furnace, comprising a horizontal refractory lined casing defining a heating chamber, a retort extending longitudinally in said heating chamber, means for feeding workpieces to one end of said retort, means for discharging workpieces from one end of said retort, transverse wall means at one end of said retort, a longitudinally extending tumble bar disposed tangentially to the axis of said retort with its edges Secured to the inner periphery thereof to form a longitudinally extending duct means, said tumble bar being provided with a series of longitudinally spaced openings for uniformly distributing atmosphere composition gases from one side of said wall means and through an opening therein to the chamber extending longitudinally of said retort, and means for imparting rotating and longitudinal motion to said retort to feed the workpieces theren in the direction toward the means for discharging workpieces therefrom.

9. In a heat treating furnace, comprising a horizontal refractory lined casing defining a heating chamber, a retort extending longitudinally in said heating chamber, means for feeding workpieces to said retort, means for discharging workpieces from one end of said retort, transverse wall means adjacent the discharge end of said retort having an opening in its peripheral edge and an inclined portion at a diametral opposite point, said wall means being adapted to prevent discharge of workpieces during normal operation and being adapted to permit the discharge of workpieces along the inclined portion when said retort is rotated a shuffie bar extending longitudinally of said retort having its edges connected to the inner periphery thereof to form a duct, means for supplying atmosphere gases to one side of said wall means and through an opening therein to said duct, said duct being provided with a series of longitudinally spaced openings to permit the atmosphere gas to be uniformly distributed throughout the entire length of said retort and pass up- Wardly through the workpieces being treated, and means for imparting feeding movement to the workpieces in said retort.

10. In a heat treating furnace, comprising a horizontal refractory lined casing defining a heating chamber, a cylindrcal retort extending longitudinally of said heating chamber and provided with conical end wall portions terminating in tubular extensions which pass through openings in opposed walls of said heating chamber, means for feeding workpieces to said retort, a discharge opening at one end of said retort, transverse wall means in said retort spaced from one of the conical wall portions and normally disposed to prevent workpieces from passing through said discharge opening, said wall means being provided With an inclined portion which, when said retort is rotated 180 from its normal position, -will uncover said discharge opening and permit workpieces to be discharged from said retort, a shuffie bar mounted in said retort and extending longitudinally thereof with its edges Secured to spaced peripheral inner surfaces of said retort defining a duct for the passage of atmosphere gases from one side of said wall means and through an opening therein to said duet, said shufile bar being provided with a series of spaced apertures to permit the atmosphere to pass upwardly through the workpieces and distribute said gases uniformly within said retort, and means for moving said retort to impart feeding motion to the workpieces fed thereto.

11. In a heat treating furnace, comprising a horizontal refractory lined casing defining a heating chamber, a cylindrical retort extending longitudinally of said heating chamber and provided With conical wall end portions, tubular extensions on said wall portions, said casing being provided with end walls having openings for the passage of said extensions, means for treating workpieces as they pass through said retort, means for feeding workpieces to said retort, a discharge opening at one end of said retort, transverse wall means in said retort to prevent workpieces from passing through said discharge opening when the retort is in a normal operative position, said wall means being provided with an inclined portion to permit discharge of workpieces through said discharge opening when the retort is rotated an angular distance of 180, a shufiie bar extending longitudinally of said retort having a series of openings and forming a duct, the tubular extension on one side of said wall means providing a passage for the introduction of atmosphere compositions to said duct through an opening in said wall means to uniformly distribute the atmosphere composition throughout the length of said retort, a conical casing on one end of said retort having a discharge tube in registry with said discharge opening, a quench tank beneath said retort filled with a quenching liquid to a predetermined level whereby said discharge tube will be submerged below said level, means for oscillating said retort and means for rotating said retort 180 to permit the discharge opening in the retort to register with the opening in said discharge tube.

12. In a heat treating furnace, comprising a horizontal refractory lined casing defining a heating chamber having opposed end walls, a cylindrical retort mounted in said casing and extending longitudinally thereof, said retort being provided with wall means at each end thereof, a longitudinally extendng plate arranged tangentially to the axis of said retort with its longitudinal edges touching and Secured to the inner periphery of said retort, said longitudinal plate extending from one of said wall members to the other wall member and being provided with a series of openings for uniformly distributing atmosphere gases in a direction upwardiy through the workpieces being treated, fan means at one end of said retort for circulating atmosphere compositions through said apertures, openings in one of said wall means to permit said atmosphere compositions to return to said fan means, the other wall means being provided with an inciined portion extending to one side of an opening in said retort, workpiece feeding means for supplying and feeding workpieces to said retort when the retort is in its normal operating position and quench tank means for receiving workpieces after they have been treated and said retort is anguiarly displaced 180 about its longitudinal axs from its normal operative position.

13. In a heat treating furnace as set forth in claim 12 in which means is provided for reciprocating said retort within said casing to feed workpeces therein and independent means for oscillating said retort and rotating the same 180.

14. In a heat treating furnace as set forth in claim 12 in which said longitudinally extending plate is provided with an inverted V-shaped rib and in which said openings are arranged on opposite sides and the top of said rib.

15. In a heat treating furnace as set forth in claim 12 in which said retort is mounted for osciilatory and reciprocating motion within said casing.

16. In a heat treating furnace as set forth in claim 12 in which said fan means comprses a rotary blower impeller rotatably supported in a shaft journaied in an end portion of said retort, and in which the wall member pro vided with a series of openings forms with said retort a blower chamber with a peripheral opening in registry With the passageway formed between said longitudinally extending plate and a peripheral portion of said retort.

References Cited UNITED STATES PATENTS 884,180 4/1908 Machlet 263--34 2,188,226 1/1940 Machlet 148-165 2,316,664 4/ 1943 Brassert et al 263-21 X 2,898,099 8/ 1959 Coriolis 263-34 3,144,245 8/ 1964 Martin 263-34 3,161,483 12/1964 Morris 34-164 X FREDERICK L. MATTESON, JR., Pr'mary Exam'ncr.

CHARLES F. GAREAU, Exam'ner.

D. A. TAMBURRO, Assistant Exam'ner. 

